<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

</body>
</html>

<script>
    function Person() {
        this.name = '89757';
//        this.age = 24;
        this.height = 168;
        this.eat = function () {
            console.log(this.name+'正在吃饭');
            console.log(this.__proto__===Person.prototype);
        }
    }
    Person.prototype.age = 20;

    var p1 = new Person();
    var p2 = new Person();
    console.log(++p1.__proto__.age);
    console.log(++p2.age);
    console.log(p2.__proto__.age);
    console.log(p2);

</script>